Treating of food products with smoke



Sept. 26, 1961 H. R. RASMUSSEN E AL 3,001,879

TREATING OF FOOD PRODUCTS WITH SMOKE Original Filed June 9, 1958 5Sheets-Sheet 1 INVENTORS.

Sept. 26., 1961 H. R. RASMUSSEN ET AL 3,001,879

TREATING OF FOOD PRODUCTS WITH SMOKE Original Filed June 9, 1958 5Sheets-Sheet 2 Era? IN V EN TORS.

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Sept. 26., 1961 H. R. RASMUSSEN ETAL 3,001,879

TREATING OF FOOD PRODUCTS WITH SMOKE Original Filed June 9, 1958 5Sheets-Sheet 3 IN VEN TORS ww m W Sept. 26., 1961 H. R. RASMUSSEN ET AL3,001,879

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Sept. 26., 1961 H. R. RASMUSSEN ETAL 3,

TREATING OF FOOD PRODUCTS WITH SMOKE Original Filed June 9, 1958 5Sheets-Sheet 5 a 5/ 2' 2/ 7?J%/EN TORS.

United States Patent TREATING OF FOOD PRODUCTS WITH SMOKE Harvey R.Rasmussen, Roselle, and Harvey J. Rasmussen,

Arlington Heights, Ill., assignors, by mesne assignments, to MeatPackers Equipment .60., Oakland,

Calif., a corporation of California Original application June 9, 1958,Ser. No. 740,820. D1-

vided and this application Aug. 7, 1959, Ser. No.

3 Claims. (Cl. 99-229) This application is a division of the priorapplication of Harvey R. Rasmussen and Harvey J. Rasmussen, Serial No.740,820, filed June 9, 1958, entitled Method and Apparatus for theProduction of Smoke for Food-Treating Purposes, which in turn is acontinuation-in-part of the now abandoned prior applications of theaforesaid Harvey R. Rasmussen and Harvey J. Rasmussen, Serial No.506,053, filed May 4, 1955, entitled Method and Apparatus for theProduction of Smoke; Serial No. 621,659, filed November 13, 1956,entitled Frictional Smoke Generator and Serial No. 621,655, filedNovember 13, 1956, entitled Power-Operated Abrading Type End ThrustCutter.

The present invention relates to an improved method and apparatus forthe production of smoke such as is used in the smoking of meats andother food products. More particularly, it relates to method andapparatus for frictionally generating smoke for food treating, and it isan object of the invention to provide an improved method and apparatusof the character indicated.

The invention also relates to abrading members for use in connectionwith frictional smoke generating methods and apparatus, and it is anobject of the invention to provide improved apparatus of this character.

Ithas already been proposed to create smoke for the curing of meats andthe like by the burning of Wood under conditions of controlledcombustion for the purpose of developing a maximum amount of smoke forthe minimum consumption of the fuel. Without exception, however, thesemethods have taken into consideration the actual burning or destructivedistillation of various types of Wood usually in the form of sawdust.

The present invention differs from those which have preceded it, in thatthe wood is not actually burned but the smoke is produced by abradingwood in such a way as to bring it to a temperature at which it willsmoke rather profusely and thereafter conducting the smoke, if desired,through suitable filters into the smoke chamber or so-calledsmoke-house. It was surprisingly found that by this method of producingsmoke the quality of the smoke could be greatly improved, and moreoverthe volume could also be accurately controlled.

It has been found that the smoke used in the treating of food productscontains certain compounds which are responsible for the desirable colorand flavor in the product treated and certain compounds which areresponsible for disagreeable tastes and undesirable color. When smokegenerated by the traditional sawdust-burning method is compared withsmoke generated by the frictional method according to the presentinvention, it is found that the frictionally generated smoke contains afar greater percentage of the desirable flavor and color components. Thesawdust-burning method results in a relatively uncontrolled amount ofdisagreeable color and flavor producing components. Accordingly, it is afurther object of the invention to provide improved apparatus and methodfor taking advantage of the benefits of generating smoke by frictionalmeans in treating food prod- .ucts.

It is a further object of the invention to provide improved means forfiltering the resulting smoke so as to the line XIV-XIV ofFIG. 12, and

Patented Sept. 26, 1961 ice prevent the introduction into thesmoke-houseof any undesired particles or smoke constituents.

' The present invention further relates to improvements which comprisepositive means for filtering and washing the smoke and for extinguishingglowing particles of wood, improved means for moving the logas it isconsumed, improved means for holdingthe wooden log, and improved meansfor readily changing a partially consumed log for a fresh one, and it isa further object of the invention to provide suchimproved apparatus;

It is a further object of the invention to provide an improvedsafetysystem for smokegenerators of the character indicated wherein theapparatus is shut down if the flow of water thereto stops or decreasesto a low level.

It is a further object of the invention to provide an abrading elementwhich is free from clogging. i

It is a further object of the invention to provide an abrading elementwhich assists in holding the end of the log in place.

It is a further object of the invention to provide an abrading elementwhich performs its function efiieiently and without overheating.

Broadly speaking, the invention comprises supporting a piece ofwoodeither vertically orhon'zontally and then attacking the wood bypressing the same against an abrading element made of iron or the like,of which the wood-contacting portions comprise a series of suitablecorrugations or teeth so as to obtain the desired amount of smokegeneration, such corrugations or teeth, for example, being provided onthe surface of a supporting disc, or being provided in the form'ofindividual members having wood-contacting surface areas similar to suchcorrugations.

Thus, in carrying out the invention in one form, a small portion or thinlayer of the end of a log is charred by frictional force and the charredportion is removed substantially simultaneously with the charringthereof.

For a better understanding of the invention, reference should now be hadto the accompanying drawings, in which FIGURE 1 is a vertical elevationof one embodiment V of the preferred form of the device;

FIG. 2 is a top plan view thereof;

FIG. 3 is a plan view of a horizontally disposed abrading disc on asomewhat enlarged scale; I

FIG. 4 is a view showing the abrading element in contact with theterminal end of a piece of wood, 'vertically disposed;

FIG. 5 shows a modification of the device whereinthe abrading elementcomprises essentially a cylinder with corrugations on its surface;

FIG. 6 is a plan view of another embodiment of the preferred form ofapparatus according to the inven tron; I. I

FIG. 7 is an elevational view, partly broken away, of the apparatusshown in FIG. .6; v I

FIG. 8 is a view on a somewhat enlarged scale, an partly in section,taken substantially along-the line VIII VIII Qe-FIG. 7; I

FIG. 9 is a view on a somewhat enlarged scale taken substantially alongline IX-IX of FIG. 7; i r 1 FIG. 10 is a view taken substantially alongline XX of FIG. 9;

FIG. 11 is a view taken substantially along line XI XI of FIG. 7;

FIG. 12 is a plan view of an abrading element according to theinvention;

FIG. 13 is a side elevational view thereof; 1 I

FIG. 14 is a sectional view taken substantially 'aldnlg 3, FIG 15 isanend view taken substantially along the. line XV-XV of FIG. 12.

FIGS. 1-5

As shown in FIGURE 1, the smoke producing appatalus: comprises avertically positioned housing. 6 on w ich there are contained variousinstrumentalities which prov-ide'the means-for carryingout the presentinvention. The primary smoke producing element consists of an abrading;element 7, which is secured by means: of a collar 8 to a suitablevertical shaft 9, which in turn through bearings 10 and 11, and isprovided with a driving pulley 121which is coupled by means of asuitable driving element such asa belt or chain 13 to a prime. moversuch as an electric motor 14, which in turn issupplied with. currentthrough the wires 15.

This abradingelement, as can be seen in greater detail in FIGS. 3 and 4,is a disc or base plate provided at its upper surface with radiallyextending protrusions 16 (for the purpose of more actively attacking theend of the piece. of wood 17 from which the smoke is to be generated; Asshown in FIGS; 1, 3 and 4, the protrusions are relatively blunt at thearea of engagement with the wood surface and have a total wood'engagingarea relatively small compared to the area of the base plate.

It is to be noted that the end of the log 17 comes into contact onlywith the tops of the protrusions or ridges 16 which are relatively bluntso as to abrade the wood, rather than to cut it. The space between theprotrusions provides a place for the charred and abraded material to go,thereby not interfering with elficient operation of the structure.

The piece of wood is clamped in suitable guide pieces 18, which may beprovided with set screws 19, and is so arranged that it may be graduallydriven downwardly toward the abrading element 7, preferably by means ofa pneumatic or hydraulic pusher element 20, the power for which isprovided through the flexible tube 21 which is provided with a valve 2-2and connected to a source of compressed air or hydraulic fluid throughthe connection 23.

It is to be understood that the arrangement is such that the wooden logmay be entirely consumed by pushing it against the protrusions ofabrading element 7.

At the upper part of the. smoke-producing instrumentality there areprovided a plurality of porous filters 24,, of which there may he thedesired number, to assure that the smoke is properly filtered before itis permitted to escape from the exhaust pipe or duct 25 to thesmoke-house.

Now, it will be immediately apparent that the position of: the filters24 above the top. of the housing can be altered; in other words, it isto he understood that if room does not permit, thev smoke may be allowedto escape from the chamber in a lateral direction, but this is not.illustrated as it is. an obvious expedient, well within the skill of theart.

In order to hold the piece of wood 17 in place, there are providedlaterally and vertically extending guide pieces 18. The guide pieces 18are controlled by means ofset screws 19, and are so arranged that theguide pieces may be swung horizontally forward of the hinges 26 andthen: upwardly so as to be kept in place by means of a hook 27 soas topermit the insertion of a fresh piece of. wood whenever the original oneis exhausted. As already mentioned, the pressure by means of thehydraulic ram 20 will servev eventually to push the wood substantiallycompletely against the abrading disc 7. The; guide pieces 18. arealsoconnected with each other by means of the transversely extendingpieces 28.

In actual operation, the member 7 isoperated at a high. enough speed togenerate a-charringtemperature so as to cause the development of largevolumes: of the desired smoke.

The bottom of the housing. may be provided with. a suitable ash pit 29from which any unburned pieces of wood which fall down into it may beremoved periodically.

It is of course axiomatic that to generate smoke of the desiredcharacter, that portion of the log, which is smoking must be raised tothe smoking temperature. The temperature should not be so high ormaintained for so long a time that flaming takes place or thatundesirable smoke components are formed. According to the teachings ofthe subject invention, only those portions of the log which are incontact with the protrusions 16 are raised to the smoking temperature.The remaining portions of the end of the log, that is, those portionswhich are in between the protrusions 16-: are not at the smokingtemperature and therefore do not produce any smoke. The abrading member7 has a substantial mass and therefore heat capacity, and it remainsessentially cool-that is, substantially below. the combustiontemperature of the wood, and it thereby assists in maintaining the majorportion of the end of the log below the smoking temperature.

In view of the fact that thesurface area of the protrusions isrelatively small compared to the surface area of the end of the log orthe general planar area of the abrading element, the stress at the pointof engagement between the protrusions 16 and the end of the log is veryhigh and therefore as these protrusions move past a particular portionof the end of the log, a high tem- 'perature is substantiallyinstantaneously created and that portion of the end of the log incontact with a protrusion reaches combustion temperature and smoke isgenerated. However, immediately behind the point of engagement of theprotrusions 16 and the end of the log 17 there is no stress and thetemperature thereat is far below the combustion temperature and no smokeis produced in this area. Accordingly, portions of the log reach thecombustion or smoking temperature rapidly and are at such temperaturefor a very short interval of time only, and the resultant smokegenerated is therefore cool and of good quality for flavor and color.Moreover, since the major portion of the end of the log remains cool orbelow the combustion temperature, there is less time for the undesirablecomponents of the smoke to be generated. That is to say, it has beenfound desirable to heat only that portion of the log at which combustionor smoking is taking place to the combustion temperature and to allowthe remainder of thelog to remain below combustion temperature.

The portion of the log in contact with protrusions 16 is charred in thesmoking process by which the desired components are driven out in thesmoke and in order for the protrusions 16 to have fresh wood to workagainst, it is desirable that the protrusions serve to remove thecharred portion of the end of the log substantially at the instant ofcharring. That is to say, for the continuous and etficient production ofsmoke, it is necessary that the charred portions of the log be removed.Thus, it has been found when a smooth flat disc is used without anyprovision for the removal of the charred end of the log, smoke will notbe generated on a continuous basis. Smoke will be generated only untilthe end of the log is charred and thereafter only heat will be generatedwhich, if the process is continued for a suflicient length of time, willresult in flaming.

As shown in FIG. 5, an alternative method is illustrated in which thepiece of Wood 17 is allowed to impinge laterally against a horizontallyrotating drum 30' which is supported in suitable bearings 31 (only oneis shown in the drawing) and which is driven over a pulley by means ofthe belt 32'. Just as in the case of the element 7, the cylindrical drum30 is provided with longitudinally extending protuberances 16' whichserve the same function of acting upon the piece of wood 11' so as toheat it and generate smoke therefrom.

'Of course it will be obvious that means must be provided for moving thepiece of Wood down against the periphery of the drum 30 for whichpurpose the same type of hydraulic pushing means shown in connectionwith the drawing of FIGS. 1 and 2 may be provided.

Theinvention is not to be circumscribed to any par ticular type of wood,as all types are suitable, but it is preferred to use some type ofhardwood, as the smoke therefrom has more desirable properties.

FIGS. 611

In these figures of the drawings there is shown a smoke generatorcomprising a housing 30 including mainsmokeproducing element 31, whichcomprises means 32 for holding a wooden log 3-3 and an abrading element34.

The log 33 is forced downwardly by weights 35 which may consist of metalbars and is directed against the abrading member 34 driven by anelectric motor 36, for example, to which it is directly coupled by thecoupling 37. The smoke is formed at the abrading member and flowing outthrough chambers 63 and 67 and outlet 69 to a smoke-house.

The means employed for holding the lower portions of the log are shownin detail in FIG. 8 and comprise a resilient arrangement whereby thelower end of the log may be held sufliciently firm and yet be allowedsome movement as the nature of the wood requires. A transverse shaft 38firmly affixed to two opposite walls .39 of the housing 30 includes oneor more rollers 40 which bear against the rear side of the log 33.Bearing on the opposite side of the log there are similar rollers 41mounted on the shaft 42. Extensions43 rigidly attached to shaft 42project along the two other sides of the log 33 to keep it laterally'inline. Secured to the shaft 38 are ring bolts to which, in turn, aresecured helical springs 45 which are fastened at one endto the ringbolts 44 and at the other end to rings 47 which are attached to theshaft 42. Obliquely positioned helical springs 46 are fastened atone oftheir ends tothe rings 47 while the outer ends of the springs aresecured to the adjacent corners of the housing 30. The force of thesprings 45. is greater than that of the springs 46 and hence the log 33is movably secured between the rollers 40 and 41.. A handle 48 isprovided'so that the log may be freed. By grasping said handle andprying the shaft 42 forward, the rollers41 are removed from the log,whereafter it can readily be displaced. Upon the insertion of a freshlog, the shaft 42 with its attached rollers 41 are allowed to springbackinto place, thus holding the new log.

As already mentioned above, metallic weights 35 arrangeable in rows areapplied to the top of the log, and these weights ride down with the logon a carrier 50 which is guided by rollers 51. The weights 35 are heldin a rack 35a to .thebottom of which a yoke 52 is attached, the combinedunit being guided bythe idlers 51. The upper end of the log is securedby the yoke 52 which is traversed by a holding screw 53, the end 54 ofwhich is permitted to dig into the log 33 (see FIG. 11). 7

As the log is forced downwardly under the influence of the weights 35and the abrading element34 is actuated by the motor 36, there will ensuea constant development of the desired smoke. The log may be made ofhickory wood, as this produces a very desirable type of smoke. i

It has been found that weights provide improved results so far asforcing the log down is concerned, as compared with more positive means,inasmuch as the number of weights is easily regulated and the rate offeeding automatically adjusts itself to variations in the hardness ofthe Wood. The density of the smoke desired and the amount of smokeneeded determine the rate of log feed and thus the number of weightsused. Accurate control may be maintained since weights in small unitsmay be added or removed.

For extinguishing glowing particles of wood, for respasm moving suchextinguished particles from the abrading chamber 62, and for washing thesmoke to remove additional impurities and to cool it, a water systeminterlocked with the driving motor is provided and functions as follows:

A pressure type of safety switch 55 (see FIG. 7) is so constructed thatit will serve to connect the motort36 and the actuating coil of themagnetic Water valve 56 to a source of electricity through circuits, notshown, when the switch button 55a is depressed manually. Thereupon, themotor 36 starts and simultaneously the mag netic water valve 56 isopened to permit flow of water from. a source 57 into the piping system.Water will hence flow through the pipes 58 and 59 and the valve 60 to aperforated pipe 61 through which a spray of water will be dischargedupwardly wherewith to quench any glowing particles that may be thrownoff the lower end of the log 33. The discharged water will thence flowalong the downwardly sloping bottom 6211 into the pit 63 from which itmay eventually be discharged through a suitable opening 64. 7

At the same time water will also flow through the pipe 65 to adownwardly facing spray nozzle 66 which is located in the chamber 67into which the smoke enters through a filtering element 68 to riseupwardly therein and to escape through opening 69 to be thereby delivered to the smoke-house (not shown).

The switch 55 is connected to the water system by pipe 58a and may be acommercially available pressurewater sprays stop. Accordingly, it isevident that when water pressure falls to such a level thatparticle-removal and smoke-washing may be inadequate, the system ceasesoperation. Manual re-starting of the apparatus becomes necessary and iseffective only if the water pressure has been restored. V

The abrading element is preferably constructed of metal and has tungstencarbide abrading members 77 and 79 suitably secured thereto, as bywelding, brazing or a sufiiciently high-melting solder.

The abrading element 75 is interiorly of abrading chamber 62 as is theperforated pipe 61. The abrading chamber is partly enclosed on all butthe right-hand side which is open and communicates with pit 63. Itincludes openings at the top for receiving the lower end of the log, andat the bottom for receiving the driving shaft of the abrading element.The abrading chamber is spaced at the front and rear from the walls ofthe smoke generator to provide openings 70 and 71, as may be seen inFIGS. 8 and 9, through which the incoming air is received. In itspassage into the generator, the incoming air cools the driving motor.

In commercial operation the abading element 34 is usually driven atabout 1400 rpm, at which speed the amount of friction is such that smokedevelopment starts about from three to five seconds after setting theapparatus in motion.

Smoke-houses are usually provided with means for pulling smoke into themand circulating it therein so that all parts of the meat being smokedwill be treated equally. Accordingly, no such parts are shown. The smokeproduced by the apparatus of the present invention is drawn bycirculating fans or their equivalents into the smokehouse from the duct69. This provides enough draft to pull the smoke from the abraded logthrough the filter 68 and through the water spray coming from nozzle 66.

The housing 30 may be made of sheet material such as stainless steelplaced on a suitable framework, a door 72' being provided for access tothe interior for changing logs, cleaning, etc.

The present invention has proven.to be eminently pracheal and useful,and is being adopted by numerous concerns which smoke meats and meatproducts, such as sausages and the like. Smoke is generated easily sothat a smoke-house may be filled with smoke in less than four minutesafter setting the abrading member into motion.

The present invention dispenses with the use of sawdust for'providingsmoke, and thus eliminates the fire hazard resulting from the storagethereof; and also saves much time and'labor such as is usually expendedin preparation for firing up the sawdust burners after a week-endshutdown. Moreover, it provides a much more convenient source of smokeand enables the more accurate control of its volume and desired density.

Figs. 12]

In these figures of the drawings the abrading element 75 also shown inFIGURES 6-10, inclusive, consists of a flatly conical piece of metal,preferably steel or iron, divided into a number of radiallyextendingsegments or vanes spatially separated, and which are providedwith raised abrading portions at their leading edges.

As shown in-FIG. 12, theremay be, for example, eight such vanes. Four ofthe vanes 76 carry such cutting portions 77 all the way to the hub orcenter of the device, while the other four vanes 78 carry the abadingportions 79-substantially to the center but terminating shortthere' ofat the inner ends of the vanes. All of the vanes extend from a hub-likeportion 80 having sufficient strength to maintain the strength andrigidity of the abrading element during use.

The abrading portions or edges 77 and 79 which preferably may be oftungsten carbide alloy pieces, are shown attached to the vanes 76 and78, respectively, by welding, brazing, or, preferably, by a high-meltingpoint silver solder. While separate abradingpieces are shown, it will beunderstood that other forms of abrading edges may be used, for example,edges integrally formed with the material of the vanes.

The entire disc is securely fastened to a shaft 81 which projectsthrough a central opening in the disc by silver soldering, for example,at 82. As shown best in FIG. 12, the end of shaft 81 projects through totheupper edge of the conical surface 83" of the disc 75 and is solderedthereto at 84 for greater strength and rigidity;

The reasons for making the edge portions 7-7 and 79 from tungstencarbide is to make them sufiiciently durable sothat the abrasionof'wooden logs may be carried out for a relatively long time withoutnecessitatingreplacement of the disc.

As will be seen bestin FIG; 15, the abrading. edge 79'extends part wayinto the. steelvanes 78; but also extends above the general planethereof, because it is the abrading edges which are mainly relied upon.to abrade the wood. Similarly for the abradingedges 77 and' vanes 76.While tungsten carbide has been foundi-tobe'a satisfactory material, it'will be: understood that other hard andfdurable materials may be used.

In the use. of: the device. according. to the invention, the end of alog'is forced: against the abradingelement 75 which is rotated, theforce being enough so that the endzof thelog'is abraded awayand'smokeis-created. The slightly conical configuration of the disccauses the end of the logto=acquire aslightly conical or tapering holewhereby the log is centered and so tends to remain in place easierwithout tending to jump off the abrading element. The abrading edges 77and 79 project above the general plane of the disc so that abradingmay'take place 8 easier, the abrading stress appearing only at theabrading edges instead of over the complete surface of the vanes.Moreover, the space behind the cutting edges forms a space for receivingthe particles before they fall-0E into the spaces between the vanes.These particles, therefore, are not chewed over and over, and the worknecessary to abrade the wood'is reduced, and the abrading processproceeds better. This latter benefit is enhanced by the spaces between thevanes, since the particles fall off the disc completely and may becarried away. The vanes, of course, must be suificiently strong to takethe necessary stresses.

Obvious modifications are intended to be included in the scope of theinventionfor example, the number of vanes and the general shape thereof.

In the form of abrading member shown in FIGS. 12- 15, the abrading edges77 and 79 are relatively blunt and have a small abrading surface areacomparedto the general area of the abrading element 75. The smallsurface of' edges 77 and 79 results, during use, of'a high local stressand consequent smoke generation without heating the portions of the lognot in contact with the edges. Here also the abrading edges remove thecharred wood portions substantially simultaneously with the charringthereof. The charred and removed material spreads into the space behindthe edges 77 and 79 and ultimately falls away.

It is the abrading edges or members or abrading protrusions which arethe important components since these do the actual work desired and not'the base supporting them.

The base may be open between the abrading edges, members, orprotrusions, and like, or closed as by plates. The base must be rigid soas to fully support the abrading members.

While particular embodiments of the invention have been shown, it willbe understood, of course, that the invention is not limited theretosince many modifications may be made, and it is, therefore, contemplatedby the appended claims to cover any such modifications as. fall withinthe true spirit and scope of the invention.

The invention having thus been described, what is claimed and desired tobe secured by Letters Patent is:

1. Themethod of treating meats and other food: products which comprisessubjecting them to smoke produced by frictionally abrading a piece ofwood while maintaining said wood below combustion temperature except atthe point of abrasion.

2. The method of treating meats and other food products which comprisessubjecting them to smoke produced by the steps of providing a woodenlog, raising the temperature of the end of said log to charringtemperature at individual areas small compared to the area of the end ofsaid log by application to such areas of a high frictional force, andsubstantially simultaneously removing charred portions of the end ofsaid log.

3. The method of treating meats and-other food-pr0ducts which comprisessubjecting them to smoke produced by frictionally abrading a piece ofwood while maintaining said wood below combustion temperatureexcept at-point of abrasion and substantially simultaneously removing abradedportions of said piece of wood.

References Cited in the file of this patent UNITED STATES PATENTS2,246,804 Lipschutz June24, 1941 2,789,877 Pfundt' Apr. 23, 1957 FOREIGNPATENTS 562,601 Canada ..Sept. 2, 1958

1. THE METHOD OF TREATING MEATS AND OTHER FOOD PRODUCTS WHICH COMPRISESSUBJECTING THEM TO SMOKE PRODUCED BY FRICTIONALLY ABRADING A PIECE OFWOOD WHILE MAINTAIN-